ACCRINT

float accrint(date issue_date, date first_interest_date, date interest_date, float annual_interest_rate, float par_value = 1000, integer payments_per_year, integer day_count_basis = 0)

Returns the accrued interest for a security (e.g. a bond) that pays periodic interest.

issue_date is the date when the security was issued. This parameter allows for a first interest period differing in duration from subsequent ones.

interest_date is the date >= issue_date for which the accrued interest is to be computed.

Automatic type conversion allows the use of date strings as arguments instead of explicit date values.

annual_interest_rate >= 0 is the security's interest rate for a whole year, i.e. payments_per_year multiplied by the amount paid on each occasion (for a bond, the coupon value) and divided by par_value.

payments_per_year is the number of interest payments (for a bond, the number of coupon payments) made in a whole year. It must be one of the following integer values: 1 (annual), 2 (semiannual) or 4 (quarterly).

day_count_basis specifies the calendar convention used to count days and compute the corresponding fraction of a year:

day_count_basis	Interpretation
0	US (NASD) 30/360: If the start date is the 31st of a month, it's set to the 30th of the same month. If the end date is the 31st of a month, it's set to the 30th of the same month unless the start date is less than the 30th of a month, in which case the end date is set to the 1st of the next month. The denominator used to compute the fraction of a year is 360.
1	Actual calendar days are counted and used to compute the fraction of a year.
2	Actual calendar days are counted. The denominator used to compute the fraction of a year is 360.
3	Actual calendar days are counted. The denominator used to compute the fraction of a year is 365.
4	European 30/360: Start and end dates that occur on the 31st of a month are set to the 30th of the same month. The denominator used to compute the fraction of a year is 360.

Accrued interest is the portion of the next interest payment corresponding to the time which has passed since the last interest payment. If 75% of the time between the last and the next interest payment has passed, 75% of the next interest payment is accrued interest, and its value (= 0.75 * annual_interest_rate * par_value / payments_per_year) will be added to the quoted price if the security is traded.

Assuming standard US date format settings, the accrued interest on the settlement date is

which equals 25. Exactly one year later, when coupon payments are occurring at the normal rate of one every six months, the accrued interest is